On Macs, the Books app has a built-in Speech function: Edit > Speech. Works with whatever books or PDFs you have in Books. Dunno what works with ebooks from Amazon; not sure what if Amazon Kindle app provides a Speech function.
Thank you, and sorry for the silly question. It’s because I user Books a lot less than Amazon Kindle, basically for historical reasons.
The Kindle Reader also has a built-in speech function, but I could not make it work, it brings up a stupid message saying “Copy Error: Your copy limit for this book has been exceeded”